If you've ever lucky enough to be selected for a minor part in a primary school play, you may have heard that - for crowd scenes - you're supposed to mutter the word "rhubarb" over and over. With several people doing so, this apparently gives the impression of a murmuring throng.
Which has led me to wonder, as anyone would, what is the equivalent of rhubarb in other languages? Because presumably, Chinese or Polish crowds don't murmur the same as English-speaking ones. So of course, I asked Google.
Shockingly, the world has not written much about this topic, but I did discover that the American equivalent is "walla" and the Japanese is "gaya". Many European languages opt for something similar to rhubarb, perhaps because it didn't occur to them to think of their own. What an oversight.
This led me to my next question: who came up with the rhubarb idea in the first place? What was it about the sound of that word layered over itself that so resembled the sound profile of English? My money's on a non-English speaker, simply because it's very hard to pinpoint the babble sounds of your own language; it's much easier to do so when you're unable to focus on meaning.
It appears I'm not the first to notice this, because there's a whole corner of the internet (much bigger than the 'history of theatrical crowd noises' corner) devoted to people not actually speaking other languages, just making rough approximations of the sounds. It's known as 'mock language' and is often, sort of, pretty racist.
But for every "hurdy gurdy" Swedish-imitating Muppet, there's a serious linguist analysing what predominant sounds characterise a language. An issue complicated by the fact that your mother-tongue limits what sounds you can even hear in another language. So my mock Italian will be different to an Indian's mock Italian, just because our brains were wired differently.
Film and television may be the death of 'rhubarb, rhubarb' though, as they require extras to mime conversations and dub stock crowd noises in later. The only answer is to support live theatre, even if it's just the primary school play.